.\" Copyright (C) 2001 Andries Brouwer . .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .TH EXIT 3 2009-09-20 "Linux" "Linux Programmer's Manual" .SH NAME exit \- cause normal process termination .SH SYNOPSIS .nf .B #include .sp .BI "void exit(int " status ); .fi .SH DESCRIPTION The .BR exit () function causes normal process termination and the value of \fIstatus & 0377\fP is returned to the parent (see .BR wait (2)). .LP All functions registered with .BR atexit (3) and .BR on_exit (3) are called, in the reverse order of their registration. (It is possible for one of these functions to use .BR atexit (3) or .BR on_exit (3) to register an additional function to be executed during exit processing; the new registration is added to the front of the list of functions that remain to be called.) If one of these functions does not return (e.g., it calls .BR _exit (2), or kills itself with a signal), then none of the remaining functions is called, and further exit processing (in particular, flushing of .BR stdio (3) streams) is abandoned. If a function has been registered multiple times using .BR atexit (3) or .BR on_exit (3), then it is called as many times as it was registered. .LP All open .BR stdio (3) streams are flushed and closed. Files created by .BR tmpfile (3) are removed. .LP The C standard specifies two constants, \fBEXIT_SUCCESS\fP and \fBEXIT_FAILURE\fP, that may be passed to .BR exit () to indicate successful or unsuccessful termination, respectively. .SH "RETURN VALUE" The .BR exit () function does not return. .SH "CONFORMING TO" SVr4, 4.3BSD, POSIX.1-2001, C89, C99. .SH NOTES .LP It is undefined what happens if one of the functions registered using .BR atexit (3) and .BR on_exit (3) calls either .BR exit () or .BR longjmp (3). .LP The use of .B EXIT_SUCCESS and .B EXIT_FAILURE is slightly more portable (to non-UNIX environments) than the use of 0 and some nonzero value like 1 or \-1. In particular, VMS uses a different convention. .LP BSD has attempted to standardize exit codes; see the file .IR . .LP After .BR exit (), the exit status must be transmitted to the parent process. There are three cases. If the parent has set .BR SA_NOCLDWAIT , or has set the .B SIGCHLD handler to .BR SIG_IGN , the status is discarded. If the parent was waiting on the child it is notified of the exit status. In both cases the exiting process dies immediately. If the parent has not indicated that it is not interested in the exit status, but is not waiting, the exiting process turns into a "zombie" process (which is nothing but a container for the single byte representing the exit status) so that the parent can learn the exit status when it later calls one of the .BR wait (2) functions. .LP If the implementation supports the .B SIGCHLD signal, this signal is sent to the parent. If the parent has set .BR SA_NOCLDWAIT , it is undefined whether a .B SIGCHLD signal is sent. .LP If the process is a session leader and its controlling terminal is the controlling terminal of the session, then each process in the foreground process group of this controlling terminal is sent a .B SIGHUP signal, and the terminal is disassociated from this session, allowing it to be acquired by a new controlling process. .LP If the exit of the process causes a process group to become orphaned, and if any member of the newly orphaned process group is stopped, then a .B SIGHUP signal followed by a .B SIGCONT signal will be sent to each process in this process group. See .BR setpgid (2) for an explanation of orphaned process groups. .SH "SEE ALSO" .BR _exit (2), .BR setpgid (2), .BR wait (2), .BR atexit (3), .BR on_exit (3), .BR tmpfile (3) .SH COLOPHON This page is part of release 3.44 of the Linux .I man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.